n | a(n) |
---|---|
0 | 1 |
1 | 4 |
2 | 13 |
3 | 40 |
4 | 120 |
5 | 354 |
6 | 1031 |
7 | 2972 |
8 | 8495 |
9 | 24110 |
10 | 68016 |
11 | 190884 |
12 | 533293 |
13 | 1484020 |
14 | 4115185 |
15 | 11375764 |
16 | 31358376 |
17 | 86223942 |
18 | 236540915 |
19 | 647556620 |
20 | 1769374931 |
21 | 4826148314 |
22 | 13142564448 |
23 | 35736448200 |
24 | 97037995225 |
25 | 263156279524 |
26 | 712795854421 |
27 | 1928547574912 |
28 | 5212430732760 |
[1,4,13,40,120,354,1031,2972,8495,24110,68016, 190884,533293,1484020,4115185,11375764,31358376, 86223942,236540915,647556620,1769374931, 4826148314,13142564448,35736448200,97037995225, 263156279524,712795854421,1928547574912, 5212430732760] |